In the recent information communication technology, optical signals and electrical signals are mutually converted in conducting information communication. In such information communication, an electro-optic hybrid circuit board having both a wiring circuit board for transmitting electrical signals and an optical waveguide for transmitting light is used. For example, the electro-optic hybrid circuit board described in patent document 1 comprises a wiring circuit board and an optical waveguide, superposed one on the other through an adhesive layer.
Patent Document 1: JP 2001-166165 A
In high-density information communication, there is a desire for communication apparatus to have reduced size and thickness. Hence, electro-optic hybrid circuit boards are also required to have a smaller thickness.